Carnarvon was the High Chaplain and Master of Sanctity of the Flesh Tearers Chapter of Space Marines. He served as the warden of that Chapter's infamous Death Company, a special unit whose members are consumed by the permanent, debilitating psychosis known as the Black Rage, until his death on Baal in ca. 999.M41 defending the Blood Angels' homeworld from Hive Fleet Leviathan.
High Chaplain Carnarvon is called the "Watcher of the Lost," for he is the lone Flesh Tearer entrusted with the sacred duty of commemorating every member of the Chapter who dies in combat or ultimately succumbs to the debilitating psychosis known as the Black Rage. He alone bears the terrible responsibility to watch over the remaining 400 Battle-Brothers of the Flesh Tearers Chapter for the onset of the Black Rage. He occupied that position for nearly 250 standard years and it was whispered by many that the strain of watching so many of his friends and comrades descend into that dreaded affliction had begun to take its toll on his sanity.
Carnarvon had the final word as to who was to be inducted into the Flesh Tearers' Death Company and who amongst those afflicted brethren were to be permanently incarcerated in the Tower of the Lost because they had fallen so far into madness that even he could no longer control them. When not in combat, Carnarvon spent most of his time within the Lost Tower, watching over his charges, ostensibly to find a path that would allow them to rejoin the Chapter. However, his constant secrecy led a great many of the Flesh Tearers to question his motives.
- Index Astartes I, ""Blood Frenzy: The Flesh Tearers Space Marine Chapter" by Matthew Sprange and Gav Thorpe, pg. 50
- The Devastation of Baal (Novel) by Guy Haley, pp. 380-384, 385, 425-435, 440-443, 493-496, 497